(1) Field of the Invention
This invention relates to an active agent-containing laminated material and a method for producing the same. More particularly, the invention relates to an active agent-containing laminated material and a method for producing the same in which impermeable films are temporarily laminated to the surfaces of an active agent-containing film and the effect of an active agent is produced only by peeling off at least one of the impermeable films.
(2) Description of the Prior Art
In the conventional art, perfumes, antifungal agents, rust inhibitors, insecticides, repellents and the like (hereinafter referred to as "active agents"), especially volatile ones, are generally used in the forms of powder, tablets or solutions in water or alcohol. In the case of a solution, paper or cloth is coated or impregnated with the solution to obtain fragrant paper, rust inhibitive paper and so forth.
There have been, however, several problems in that the effect of an active agent is liable to be lost in a short period of time and the heat-sealable property and water-proofness of the active agent-containing materials are not satisfactory. Meanwhile, several polyolefin compositions are proposed which are prepared by mixing active agents into plastics such as polyolefin by using carriers so as to regulate the rate of releasing of the active agents to be slow and constant.
For example, in British Pat. No. 1,538,085, it is proposed that a master batch of perfume-containing ethylene-vinylacetate copolymer is blended into polyethylene to obtain a composition and this composition is used for refuse bags and so forth.
Similar examples are disclosed in many patent specifications such as U.S. Pat. No. 4,095,031 (Japanese Laid-Open Patent Publication No. 53-98352); Canadian Pat. No. 844,014; U.S. Pat. No. 3,553,296; and Japanese Laid-Open Patent Publication No. 56-121560. These compositions are used singly or in combination with other plastics to form film materials and injection molded goods.
In order to avoid undesirable release of active agents before use and to prolong the serviceable life of active agents, it is desirable that these products are hermetically sealed with impermeable wrapping materials until they are used.
Meanwhile, in the present status of the industry, there are few instances of laminated materials that are made of the combination of a composition of active agents such as perfume and polyolefin with a substrate material made of other plastics of paper.
In the field of volatile rust inhibitors, a few patents are known as an inevitable consequence of the manner of uses (U.S. Pat. No. 282,980; U.S. Pat. No. 3,080,211 and Japanese Patent Publication No. 52-13988). The laminated materials described in these patents are produced by steps such that a volatile rust inhibitor is dissolved in an emulsion resin or a solvent and applied to a film to obtain a covering film and the covering film is laminated with a base film, or a plastic layer containing a rust inhibitor is bonded firmly to a base film. These are used in direct contact with metallic goods in order to prevent the goods from gathering rust.
Perfumes are used not only for cosmetics, soaps, detergents, tooth pastes, medicines, bath agents, cakes, chewing gum, alcoholic liquors and refreshing beverages but, with the recent changes in life style, fragrences are utilized in a variety of ways to make the daily mode of life more comfortable and enjoyable.
In order to meet the above requirement, the inventors have proposed posters, postcards, bookmarkers, labels, greeting cards, interior wall materials and packaging materials that are made of laminated materials of a perfume-containing polyolefin composition and a substrate material such as paper.
These laminated materials are those prepared by firmly bonding active agent-containing polyolefin compositions to substrate materials like the foregoing rust inhibitive laminates. Therefore, it is necessary that the laminated materials are hermetically sealed with impermeable films in order to prevent the active agents from being released before use.
To this end, it is desirable that the outsides of these laminated materials be covered by films. For this purpose, the covering film must be temporarily applied to the laminated material and, in addition, it is desirable that the covering film can be reapplied after it has been peeled off.
In order to meet the above requirement, when an adhesive agent is used, it remains on the substrate material leaving a sticky surface. Where the active agent is a perfume, the fragrance of the perfume will be degenerated.
Static electricity was utilized as an adhesive means to secure the covering film. Since this temporary adhesive force had to be weak enough to permit removal of the film, it was difficult to completely seal off the fragrance when the covering film was reapplied.